Government laws and regulations, such as the Communications Assistance for Law Enforcement Act (CALEA) in the United States, can require network providers to be able to intercept specific network traffic in response to lawful requests from law enforcement agencies and/or other government entities. Prior techniques for lawful interception of digital network traffic include active techniques and passive techniques. Prior active techniques involve tagging network packets associated with entities whose network traffic is to be intercepted. Prior passive techniques involve snooping or, in other words, monitoring and examining the control plane signaling exchanges between network elements (e.g., routers) to remain in-sync with the routing state of the network traffic to be intercepted.
Wherever possible, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts, elements, etc.